The present disclosure relates to gas purifiers and more particularly to packed resin or dry chemical bed gas scrubber systems for the treatment of effluent gases produced in semiconductor manufacturing.
In the fabrication of semiconductor devices toxic and corrosive gases, including halogenated species, are used in both etch and deposition processes. After use in a process chamber, the effluent gas stream must be treated before being exhausted into the environment. Several scrubbing devices attachable to an exhaust of the process chamber are known in the art.
Known scrubbing devices consist generally of three types; those which burn the flammable components of the effluent gas stream, those which decompose water soluble components of the effluent stream in a wetting method and those which adsorb toxic components using adsorbents to chemically and physically decompose the toxic components. Stand-alone scrubbers of the adsorptive type must be periodically replaced as the adsorbent material is used in adsorbing the toxic components and as the adsorbent becomes deactivated with the by-products of reactions between the adsorbent and toxic compounds.
In addressing the problem of determining when to replace the stand-alone scrubber, prior art devices generally employ two techniques. A first technique includes tracking a change in the weight of the scrubber. Such a technique is utilized, for example, in the Ebara Corporation Model No. 3-0/6-0-/9-0. This technique provides a method by which the end of life of the adsorbent material is indicated but does not accurately provide a method for predicting the end of life of the adsorbent material, and is not particularly accurate as changes in the weight of the scrubber attributable to other causes are not taken into consideration.
A second technique includes monitoring a color change in the adsorbent resin wherein the color change is observable through a sight glass. Such a technique is utilized, for example, in the Japan Pionics Corporation Model No. PCF-60B-CT. As in the case of the first technique, the second technique provides a method by which the end of life of the adsorbent material is indicated but does not provide a method of predicting the end of life of the adsorbent material. Further, a subjective element is introduced by the person viewing the color change which introduces human error into the end of life determination.
There therefore exists a need for a stand-alone scrubber system of the packed resin or dry chemical bed type which provides for the accurate, objective and automatic prediction of the end of life of the adsorbent material.
A packed resin or dry chemical bed scrubber system and method for the treatment of effluent gases produced in semiconductor manufacturing is disclosed. In a preferred embodiment, the system includes a packed resin or dry chemical bed having a first resin or dry chemical layer packed between two layers of a second resin or dry chemical. A bottom screen and a top screen are provided for supporting the packed resin or dry chemical bed within a canister and to provide a substantially laminar flow of the effluent gases through the packed resin or dry chemical bed. An end of life detection and prediction system includes a plurality of spaced thermocouples positioned within the first resin or dry chemical layer and operatively coupled to a processor for monitoring the movement of an exothermal wavefront at each position and for predicting an end of life condition of the first resin or dry chemical layer.
The packed resin or dry chemical canister includes a bottom plenum and a top plenum disposed at opposite ends of the packed resin or dry chemical bed. A dispersion nozzle is disposed within the bottom plenum at an inlet formed in communication with the bottom plenum. The dispersion nozzle includes a plurality of apertures for directing the flow of the effluent gases from the semiconductor fabrication tool into the bottom plenum. The apertures are sized and configured to eliminate back pressure into the semiconductor fabrication tool and to disperse the effluent gases into the bottom plenum for subsequent laminar flow through the packed resin or dry chemical bed.
A top portion of the canister includes an outlet in communication with the top plenum. The top portion further includes a dome of arcuate cross section. This configuration is optimized to provide for substantially laminar flow of the effluent gases through the packed resin or dry chemical bed.